Studies on the Cause of Death in Tetanus

Human Tetanus as a Respiratory Problem

¹ Department of Tropical and Infectious Diseases, Hospital das Clinical da Universidade de Sao Paulo

A group of patients with generalized tatanus has been studied with the view of determining whether respiratory function was sufficiently impaired to be considered life-threatening. It has been found that:

1. Vital capacity and maximum breathing capacity were all low during the acute phase of the disease, even in benign tetanus. These volumina returned to normal after a period of two to three months. Pulmonary compliance, maximal inspiratory and expiratory flow rates, and cost of breathing were all abnormal in the one patient in whom these studies were made.

2. Reduced ventilatory capacity in tetanus is not a problem of chest rigidity alone. Roentgenographic studies of seven patients showed fixation of the diaphragm in the expiratory position in three and a decrease in mobility in an additional patient. Follow-up roentgenograms of two of the four patients showed complete restitution on diaphragmatic motion after 34 and 60 days.

3. Intravenous administration of mephenesin and thiocolchicide did not alter vital capacity and maximum breathing capacity. In the absence of diaphragmatic immobility such a procedure could be used for the evaluation of muscle relaxing agents.

4. Arterial oxygen saturation was not reduced to levels which by themselves could be condidered a threat to life. Carbon dioxide retention was not observed.

The studies reported suggest strongly that respiratory failure is rarely a direct cause of death in tetanus.